IMPOSITIONS ON ENERGY BALANCE IN PROLONGED FLIGHT: WIND-TUNNEL MEASUREMENTS WITH “MODEL BIRDS"

Abstract

ABSTRACT Metabolic and thermoregulatory aspects of prolonged wind-tunnel flights of pigeons (Columba livia) are presented. Measurements and calculations of mass rates, gas volumes, and heat loss are given in a detailed table. The wind tunnel and the testing and training procedures are described. Metabolic power and respiratory exchange rates are given as functions of flight time within the first hour of flight; boundary conditions are body mass, feeding, and seasonal conditions. The changes were drastic, but metabolic power during the first hour of flight was only 3% higher than any succeeding hour. Mass loss and evaporative water loss at different ambient temperatures are given as functions of flight time within the first hour. Idealized time plots of fuel consumption, metabolic water production, and mass losses are derived from these functions. Heat loss due to metabolic water loss accounted for 9%, and nonevaporative heat loss, to 77% of total heat loss; therefore 14% was due to body water loss at the ...